Data on women in the Washington, DC Cardiovascular (CV) Health and Needs Assessment provided initial insights into mHealth user engagement for the development of a physical activity (PA) intervention cohort. Among women in the assessment (99% African American mean age=59 (12) years), 90% had a body mass index (BMI) categorized as overweight or obese, with 30% having Class-I obesity, 19% having Class-II obesity, and 17% having Class-III obesity. Across weight classes, PA decreased (p0.05) and self-reported sedentary time increased (p0.05). Although diastolic blood pressure and fasting blood glucose significantly increased across weight categories among women, blood pressure, cholesterol, and glucose were relatively well-controlled with mean values consistent with ideal or intermediate levels of the American Heart Associations CV health cut-points. PA-monitoring system compliance remained above 60% for the 30-day study period among women participating in the study, with similar compliance among women with obesity over the study period. Therefore, deployment of mHealth technology with CBPR strategies can help target PA for improving cardiovascular health among African American women in resource-limited communities. As a first step for the intervention, we gathered qualitative data to inform the development of a mobile app that promotes PA among African American women in Washington, DC. We recruited a convenience sample of African American women (N=16, age range 51-74 years) from regions of the Washington, DC metropolitan area with the highest burden of cardiovascular disease. Participants used an app created by the research team, which provided motivational messages through app push notifications and educational content to promote PA. Subsequently, participants engaged in semi-structured focus group interviews led by moderators who asked open-ended questions about participants' experiences of using the app. Focus groups were audio-recorded and transcribed verbatim, with subsequent behavioral theory-driven thematic analysis. Key themes based on the Health Belief Model and emerging themes were identified from the transcripts. Three independent reviewers iteratively coded the transcripts until consensus was reached. Then, the final codebook was approved by a qualitative research expert. In this study, 10 main themes emerged. Participants emphasized the need to improve the app by optimizing automation, increasing relatability (eg, photos that reflect the target demographic), increasing educational material (eg, health information), and connecting with community resources (eg, cooking classes and exercise groups). Involving target users in the development of a culturally sensitive PA app is an essential step for creating an app that has a higher likelihood of acceptance and use in a technology-enabled intervention. This may decrease health disparities in cardiovascular diseases by more effectively increasing PA in a minority population.